(Reward: 15 points) This is for Lesson 6 Unit 4 (connexus students, grade 11. Quiz part 2.
(PLEASE SHOW THE PROCESS. And please answer all 3.. Please and thank you!)

Question 1: Solve the system by substitution.
-x-y-z=-8
-4x+4y+5z=7
2x+2z=4

Question 2: Solve the system by elimination.
-2x+2y+3z=0
-2x-y+z=-3
2x+3y+3z=5

Question 3: Given the system of constraints, name all vertices of the feasible region. Then find the maximum value of the given objective function.
Constaints:
x≥0
y≥0
y≤ 1/3x+3
5≥x+y
Objective Function: C=6x-4y

Thank you in advance!! This helps me (and other students) out :)